1. Field of the Invention
This invention relates to an image forming apparatus, and more particularly relates to an image forming apparatus that uses replaceable consumables.
2. Description of Background Art
When an image forming apparatus is used as a copying machine, an electrostatic latent image is formed on a photoreceptor, a toner is supplied to be adhered to the electrostatic latent image in order to make it visible, and the image is transferred with the toner onto a sheet of paper to produce an output image. Outputs of images consume toner, and therefore the consumed toner should be supplied from outside supply sources. Generally, the consumed toner is supplied by replacing the empty toner cartridge with a toner cartridge filled with toner.
Toner serves as a component for forming images and has various features. For example, toner has a charging performance and a particle size distribution to improve the image quality. The surface property of toner functions to prevent a photoreceptor and a developing unit from damage. The features that the toner should have depend on the image forming apparatus and the photoreceptor and developing unit contained therein. Specifically, the use of genuine toner suitable for the image forming apparatus prevents the photoreceptor and other units from damage and can create high-quality images. These sorts of toner are manufactured by people well-versed in the toner features, such as manufacturers of the image forming apparatuses.
However, some people, who are ill-versed in the toner features, manufacture and sell toner. Such “non-genuine toner” that is formed by analyzing and imitating toner manufactured by the image forming apparatus manufacturer, that is to say “genuine toner”, is passable to form visible images. However, because non-genuine toner does not have exactly the same features as genuine toner, it is very difficult to obtain high-quality images with the use of non-genuine toner. Besides, such non-genuine toner may badly wear the photoreceptor, for example, resulting in failure of the image forming apparatus.
Japanese unexamined patent publication No. 2001-125462 discloses a technique to determine whether a cartridge is an improper cartridge that has been refilled with consumables. The image forming apparatus according to the publication is designed to detect whether or not the cartridge loaded in the image forming apparatus is proper, and prohibit the printing operation when the cartridge is improper.
Most users who use the non-genuine toner to output images hardly notice the above-described failure caused by the non-genuine toner. This puts users at a disadvantage. In addition, the use of non-genuine toner in the same manner as genuine toner does not provide high-quality images.